From a seat and service perspective there's really no difference between the front and rear business cabins on the 772. You may get served slightly quicker in the front cabin, and also no economy pax passing through during boarding, so the front cabin is a tad better in that regard.

On the 772's the bigger question is whether you want to guarantee a forward (or rear) facing seat should you get a Concept D config, as well as a non-connected seats if any are available.

If traveling solo on the 772 my go-to is 7A or 7L as they are non-connected windows.